Broughton Katrina J, Bate Eleanor L, Cutler Corey W, Allen Christopher N, Thompson Alan J E, Conaty Warren C
Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, Narrabri, NSW, Australia.
Front Plant Sci. 2024 Dec 4;15:1451993. doi: 10.3389/fpls.2024.1451993. eCollection 2024.
Crop yields in food and fibre production systems throughout the world are significantly limited by soil water deficits. Identifying water conservation mechanisms within existing genotypes is pivotal in developing varieties with improved performance in water-limited conditions. The objective of this study was to screen Australian germplasm for variability in the transpiration response to progressive soil drying using a glasshouse dry-down experiment. It tests the hypothesis that water conservation traits may provide tolerance to water stress, particularly when combined with other drought stress traits.
Three glasshouse experiments were conducted to identify whether there are differences in the fraction of transpirable soil water (FTSW) threshold values for transpiration decline among six cotton genotypes. We also assessed whether genotype dependent responses to progressive soil drying are evident from leaf-level physiology, by measurement of gas exchange parameters.
Significant variation in the FTSW threshold for transpiration decline between six genotypes was found, ranging from 0.13 to 0.29. Genotypic variation in the response to soil drying was also observed from leaf level physiology, with reductions in stomatal conductance and photosynthetic rate coinciding with when the FTSW threshold was reached.
Genotypes that limit transpiration at high FTSW can conserve water earlier in the season to maintain productivity during extended dry periods. Therefore, these genotypes may provide physiological traits that improve productivity in water-limited environments. This research is important as rainfall and water resources for irrigated agriculture are predicted to decline. The development of drought tolerant germplasm for the Australian cotton industry will be beneficial in the projected increasingly frequent limited water environments resulting from a changing climate.
全球粮食和纤维生产系统中的作物产量受到土壤水分亏缺的显著限制。识别现有基因型中的节水机制对于培育在水分受限条件下性能更佳的品种至关重要。本研究的目的是通过温室干燥试验筛选澳大利亚种质，以研究其在土壤逐渐干燥过程中蒸腾作用响应的变异性。该研究检验了这样一个假设，即节水性状可能提供对水分胁迫的耐受性，特别是与其他干旱胁迫性状结合时。
进行了三项温室试验，以确定六种棉花基因型在蒸腾作用下降时可蒸腾土壤水分（FTSW）阈值是否存在差异。我们还通过测量气体交换参数，评估了从叶片水平生理学来看，对土壤逐渐干燥的基因型依赖性响应是否明显。
发现六种基因型在蒸腾作用下降的FTSW阈值上存在显著差异，范围从0.13到0.29。从叶片水平生理学也观察到了对土壤干燥响应的基因型变异，气孔导度和光合速率的降低与达到FTSW阈值的时间一致。
在高FTSW时限制蒸腾作用的基因型可以在季节早期节约用水，以在延长的干旱期维持生产力。因此，这些基因型可能提供在水分受限环境中提高生产力的生理性状。这项研究很重要，因为预计灌溉农业的降雨量和水资源将会减少。为澳大利亚棉花产业培育耐旱种质将有利于应对因气候变化导致的预计中日益频繁的有限水环境。
